Centrifugal fan.



Nd. 681,389. Patented Aug. 27, I90l. s. c. DAVIDSON.

CENTBIFUGAL FAN.

' (Application filed Dec 19. 1899.)

(No Modal.)

INVENTOR:

By Attorneys, Q (Rm '6, @F m UNITED STATES PATENT OFFICE;

SAMUEL CLELAND DAVIDSON, OF BELFAST, IRELAND.

-CENTRIFUGAL FAN.

SPEGIFIGATION forming part of Letters Patent No. 681,389, dated August 2'7, 1901.

Application filed December 19, 1899. Serial No. 740,874. (No model.)

To all whom it may concern.-

Be it known that I, SAMUEL CLELAND DA- VIDSON, a subject of the Queen of Great Britain, residing in Belfast, Ireland, have invented certain new and useful Improvements in Centrifugal Fans, of which the following is a specification.

My invention relates to rotary fans, especially of the centrifugal type, and aims to provide an improved connection between the fan and the motor by which it is rotated. In this type of fans it is common to couple the rotary member directly to an electric motor and to fix the stationary member or casing directly to the motor-shell, so that the casing is supported from the motor. This has usually been done by a connecting-casing which is fixed between the fan-casing and the motor-shell. It has been found that in operation the fan tends to either drive or suck the oil from the motor-bearings, due to back pressure or exhaust, according to the condition under which the fan is operating. My invention aims to avoid this disadvantage by providing Venti lating-passages between the space inclosed by the connecting casing and the outer air, whereby the pressure within the casing is maintained at approximately normal atmospheric pressure.

My invention also provides a means by which the direction of delivery from the fancasing may be changed as desired, thus permitting the adjustment of a single fan to Varying conditions of use.

Referring to the drawings, in which I have shown my invention as applied to a fan coupled to an electric motor, Figure 1 is a sectional elevation of the preferred form of my invention, and Fig. 2 is a rear elevation.

In the drawings, A designates a suitable base or support for the motor B, which latter is here shown as an electric motor of common type, inclosed in a protecting-shell B, which is fixed to the base A by bolts 0, passing through suitable flanges formed in the shell.

To the front of the shell B is fixed a casing D, which is preferably formed as an integral part of the motor-shell and which forms an intermediate connecting-casing between the latter and the fan-casing H. The casingD is formed on its exterior with an annular vertical flange E, to which the fan-casing H is fixed by suitable bolts J, passing through the flange and casing. The holes through which the bolts J pass are spaced apart equidistantly around the flange E and easing H, so that the latter may be turned in any direction to bring the delivery-nozzle P to the position best suited to theindividual requirements,.whereupon the casing may be bolted in its adjusted position. This permits a delivery of the fluid operated on in any direction, two of the many positions being shown in dotted lines at P and P in Fig. 2 and a third in full lines at P. The base A should be of sufficient height to permit the nozzle P to pass to its lowest position (shown indotted lines at P without striking the floor. The fan-casing is supported temporarily during its adjustment by the connecting-casing D, which is shown as extending a short distance into the fan-casing. The shaft G of the motor B preferably extends through a suitable gland or stuffingbox into the casing H, and preferably, as in the construction shown, the rotary member of the fan is mounted directly upon the shaft. The type of fan shown comprises numerous thin elongated blades L, which are arranged in drum form and are fixed at their inner ends to a diskN, which is fixed to a suitable 8o hub K, mounted upon the shaft G. At the opposite or intake end of the fan the blades L are fixed to an annular support N, which encircles the blades at their outer edges. The intake end of the fan faces a suction-eye or inlet-opening M, formed in the casing, which latter is preferably provided with a suitable mouthpiece or funnel M for directing the fluid into the eye. The fluid operated on is taken axially into the intake-chamber of the fan and is discharged circumferentially into the casing through the spaces or ports between the blades L, as shown by the arrows in Fig. 1, whence it escapes through the nozzle P. When operating as an exhaust,- 5 with a free discharge through the delivery nozzle,the rapidly-moving fluid tends to cause a suction from the interior of the casing D into the fan-casing around the edges of the disk N. This suction tends to draw the oil I00 from the motor-bearings through the stuffingbox of the shaft G, so that the bearings heat.

When the fan is operating as a pressurepump, the fluid tends to pass around the disk Ninto the casing D, thus tending to force the oil from the motor-bearings in a direction opposite that just described. By my present invention I obviate both these dif ficulties by forming one or more ventil-ating-openings O in the casing D, so that a communication is established between the 1 interior of the casing and the outside air, whereby the pressure in the casing and motor-shell is maintained substantially equal. t Thus an increase of pressure in the casing D will cause an outflow throughtheopenings O, as shown by the arrow, while suction from the fan-casin g will cause flow in til-6101pposite direction.

It is .not essential to the present invention that :an electric motorsihouid be used or that the rotary member of the fan should be d-i-; recti'y mounted upon the :m-otorashaft, as my mvention may be advantageously used with other motors and whenever the proximity of the fan to the motor is such as to produce any undesirable pressure in the intermediate connectingpasing.

What I claim is 1. zlhe combination of a rotating fan, motor :for driving it, and ,arcosnnectingeasing between said fan :and said motor supporting one of said members from the other, 1

said casing having ventilatingopenings to;

permit the circulation of air through said casing.

2. The combination of a motor, a rotating fan, a casing for the fan, a driving-shaft for the fan connected to said motor, and an intermediate connecting-casing between said motor and said fan-casing and supporting one of said members from the other, having 40 ventilating-openings to permit the circulation of air therethrough.

3. The combination of a motor, a shell inclosing said motor, a rotating fan, a casing for said fan, and an intermediate connectingcasing between said motor-she11 and said fancasing and supporting one of said members from the other havingventiiatingkopemings to permit theiciirculati-on of air therethrongh.

4:. The combination of :a motor, a sheill inclosing .said motor, a centnttugalxfan rotated by said motor and having its inner end closed, a casing for said fan, and 'an intermediate casing connecting said ,fan-cas'izngrto said shell and supporting .saidcasing from 

